1. Field of the Invention
The present invention relates to a device to produce gradient soft irradiation through the use of off-axis placement of a radiation source within a spiral reflector which completely encloses the source. The present invention also relates to the use of optical coatings in conjunction with the device in order to enable the device to emit selective narrow bandwidths of radiation.
2. Description of the Prior Art
A. Currently Used Collimators
Currently used collimators, such as lensing and parabolic reflectors, emit collimated, spatially coherent electromagnetic energy. At the aperture of these collimators, all electromagnetic energy is spatially coherent. Spatially coherent light will produce sharp shadows.
B. Reflector Design
Spiral based curves have been used for the collection of energy. For example, U.S. Pat. No. 3,974,824, Solar Heating Device, discloses a solar heating device utilizing a cylindrical reflector with a spirally extending section and a parabolically section for concentrating solar energy on an axially disposed absorber carrying a fluid to be heated. In this device, the incoming energy is concentrated along the axis of the spiral.
Additionally, spiral reflectors have been used to illuminate walls, as per U.S. Pat. No. 4,564,888, Wall Wash Lighting Fixture. The reflector of this device, however, discloses only the use of a light bulb within a reflector which does not fully enclose the bulb.
C. Light Filter Design
Ordinary light filters often absorb 50-90% of the desired wavelengths to eliminate the unwanted portion of the spectrum.
It is an object of this invention to provide a device for soft irradiation having a spiral shaped reflector used with an electromagnetic radiation source positioned such that the source is shielded from direct view and is located off of any focal axis of the reflector, such that output from the source undergoes at least one reflection and has soft or multi-angled dispersion without spatial collimation.
It is a further object of the invention to provide impingement cooling of the radiation source to allow efficient use of a high intensity radiation source.
It is another object of the invention to allow output in selective bandwidths through the use of optical reflectance coatings on the surface of the reflector or transmission filters.
It is also an object of the invention to combine multiple reflectors in conjunction with one another to evenly illuminate complex or large surfaces.
More particularly, the present invention is directed to off-axis localization of linear and point sources of electromagnetic irradiation within spiral curve reflectors to produce gradient soft irradiation with approximately linear power degradation with respect to distance. The joining of multiple spirals can be adjusted to uniformly irradiate complex surfaces. In contrast to currently used collimators, such as lensing and parabolic reflectors, the radiation emanating from the source of this invention is dispersed spatially at the aperture without parallel rays, producing a soft pattern of irradiation. Additionally, the present invention is directed to the application of optical reflectance coatings to the inner surface of the spiral reflector to produce emission of selective narrow bandwidths of radiation from a broader bandwidth source. The invention apparatus will have application to the fields of phototherapy (both adjuvant and endogenous reactions), tanning, photography, lithography, electromagnetic activated chemical reactions, and heat transference. With both pulsed and continuous light sources there will be specific utilities to this design.
Examples of arrangements within the scope of the present invention are illustrated in the accompanying drawings and described hereinafter, but it will be understood that neither the drawings nor the descriptions thereof are presented by way of limitation and that other arrangements also within the scope of the present invention will occur to those skilled in the art upon reading the disclosure set forth herein.